Device for sifting and stratifying ores



Dec. 20, 1966 G. s. KJARVAL 3,292,781

DEVICE FOR SIFTING AND STRATIFYING ORES Filed Feb. 6, 1964 v 2 Sheets-Sheet 2 IN V EN TOR.

BY L/z 3M Attorney GUNNAR s. KJARVAL United States Patent 3,292,781 DEVICE FOR SIFTING AND STRATIFYING ORES Gunnar Svenson Kjarval, 1013 NE. 91st Ave., Portland,

Oreg. 97220; Gunnar C. Kjarval, executor of the estate of Gunnar S. Kjarval, deceased Filed Feb. 6, 1964, Ser. No. 343,079 15 Claims. (Cl. 209-44) This invention relates to improvements in a machine for panning gold and other heavy ores which occur in finely divided condition is sand and gravel.

Objects of the invention are to provide an ore concentrating machine for the purpose described which is more efiicient than conventional machines whereby it will recover a higher percentage of the valuable material, to provide a machine having a novel and improved mode of operation, to provide a machine which performs a double panning operation, and to provide a machine which is small enough to be conveniently portable and yet which is power operated so that it can handle a relatively large amount of material.

The present machine performs a double panning operation by means of a carriage which is reciprocated by a small gasoline motor or the like. The coarse material is removed in a first stage of the panning operation and a fair amount of concentrates is recovered in this first stage. Then the material passes to a second oscillating pan which retains'the balance of the fines and discharges the intermediate size aggregates. Both pans are incorporated in an oscillating carriage which in the preferred embodiment is of a size to receive ore-bearing sand and gravel by the shovelful. It is within the scope of the invention, however, to construct the machine on a larger scale and adapt it for conveyor feed or other means to handle a greater flow of material.

The invention will be better understood and additional objects and advantages will become apparent from the following description of the preferred embodiment which is illustrated in the accompanying drawings. Various changes may be made, however, in the details of construction and arrangement of parts, and all such modifications Within the scope of the appended claims are included in the invention.

In the drawings:

FIGURE 1 is a top plan'view of a machine embodying the principles of the invention;

FIGURE 2 is a longitudinal sectional view taken on the line 22 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary view taken on the line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged fragmentary cross sectional view taken on the 'line 44 of FIGURE 2; and

FIGURE 5 is an enlarged cross sectional view taken on the line 5-5 of FIGURE 2.

The base frame is made in the form of a platform to support a carriage 11 for reciprocation by a suitable motor such as a small gasoline engine 12. This platform is equipped with a pair of longitudinal rails 13 to support the carriage wheels 14. The carriage frame includes a rear cross member 15 which is pivotally connected to a pitman rod 16 on a crank 17. Crank 17 is connected to the power output shaft 18 of the engine which is geared down to provide a suitable rotational speed.

Mounted on base frame 10 behind the carriage frame member 15 is a transverse spring reaction bar 20'. This bar is apertured to slidably receive pitman rod 16 and a pair of longitudinal rods 21 having forward ends extending through apertures in carriage frame member 15 as shown in FIGURE 3. The forward ends of these rods are threaded to receive nuts 22 and the rear ends are "ice threaded to receive nuts 23. The forward ends of the rods carry coil springs 24 which are compressed between carriage frame member 15 and stationary bar 20, and the rear ends of the rods carry coil springs 25 which are compressed between nuts 23 and the bar 20. The opposed springs 24 and 25 are in balance when pitman rod 16 is in mid stroke as, for example, when crank 17 is vertical as in FIGURE 2.

When the carriage moves forward or to the right in FIGURES 2 and 3, the compression of rear springs 25 is increased while the compression of front springs 24 is decreased, and when the carriage moves rearward from the mid position shown, the spring action is reversed. Thus, as the carriage reciprocates, the front and rear springs alternately store energy and then impart this energy to the carriage to provide an oscillating system in which a large part of the energy for maintaining oscillation is derived from the springs whereby the motor 12 need supply only sufficient energy to overcome friction in the system. Rear springs 25 assist in arresting the forward mot-ion and reversing the carriage and frontsprings 24 assist in arresting the rearward motion and accelerating the carriage forward so that the major part of the decelerating and accelerating forces are not imposed on the motor. Also, since the carriage reversals occur in simple harmonic mot-ion they impose a minimum shock on the apparatus so that the parts will not wear out quickly.

The spring tension may be adjusted by nuts '22 so that the carriage and spring combination have a natural period of oscillation corresponding approximately to the movements of pitman rod 16 when the carriage is in operation with its normal load of sand, gravel and Water. This natural frequency will, of course, vary with the size and capacity of the machine, and the motor speed may be coordinated with the adjustment of nuts 22 and 23 to provide an optimum frequency of oscillation of the carriage for the most effective panning action.

Referring back to FIGURE 2, the carriage 11 has an upper pan 30 and a lower pan 31. These two pans are integral with each other and the forward end of the pans is mounted on horizontal pivot pins 33 on the front end of the carriage whereby the pans may be tilted up to vertical position as shown in broken lines for emptying. The inclination of the pans in operating position may be adjusted by selecting the proper thickness of block 35 which supports the pans on rear transverse carriage frame member 15.

Upper pan 30 has a fiat bottom 36 which slopes forward at a small angle from the horizontal and lower pan 31 has a flat bottom 37 Which slopes rearward at a small angle from the horizontal. By using a block 35 of greater thickness, the former angle is increased while the latter angle is diminished, and by using a block 35 of lesser thickness the former angle is diminished while the latter angle is increased. Removable block 35 provides a convenient means for adjusting these angles in the field to achieve best results. The forward end of the upper pan is connected to the rear end of the lower pan by a vertical wall 38 which is preferably merely a mid portion of a continuous sheet of metal which forms the bottoms of both pans.

Bottom wall 36 of the upper pan is equipped with a plurality of upstanding transverse n'ifies 39 and above these riflies are cross bars 40 supporting a removable screen 41. At the lower or forward end of screen 41 is an upstanding flash board 42 of relatively low height. Preferably, the rifiies 39 are mounted in a separate removable tray or pan 39a for convenience in taking out the concentrates.

A discharge apron 45 extends forward over the lower pan from the lower end of screen 41. The inclination of the apron may be adjusted by a vertical supporting screw 46 which is supported at its lower end on an extended overflow discharge lip 47 at the forward end of the lower pan. The front end of the apron is spaced above the lip 47 to allow ample clearance for free discharge of material from the lower pan. Lip 47 is slightly lower than the lower end of bottom wall 36 of the upper pan.

Spaced forward from the intermediate vertical wall 38 is a removable vertical partition wall 50 supported in guides 51 on the opposite side walls of lower pan 31. This partition wall terminates a distance above the bottom 37 of pan 31 and forms a throat or vertical discharge passageway 52 from the front end of the upper pan to the rear end of the lower pan. Wall 50, which is preferably a plate of sheet metal, maybe detachably connected at its upper end with the apron 45 and screen 41 for removal of these parts. The height of the lower end of screen 41 and the upper end of apron 45 is adjusted by blocks 53 under the lower end of wall plate 50 in the guides 51.

A free swinging pendulous agitator 55 is suspended for fore and aft swinging movements above the bottom 37 of lower pan 31. This agitator comprises a heavy weighted transverse bar, preferably of wedge shape in cross section, having a V-shaped front face 56 which is wide in a vertical direction and a relatively narrow rear edge 57 which may be equipped with a depending pusher plate 58. Agitator bar 55 is suspended at its ends by a pair of hanger arms 60 having hooked upper ends 61 on a transverse shaft 62. The hooked ends 61 may be lifted off shaft 62 for removal of the agitator 55 and the transverse shaft 62 is detachably mounted at its ends in the upper side walls of lower pan 31 above the apron 45 whereby shaft 62 may be removed in order to remove the apron 45. The lower pan has a front end wall 48 of less height than wall 38 which forms its back end wall.

Operation In a small portable machine ore-bearing sand and gravel is delivered to the screen 41 of the upper pan by shovel but in a larger machine it may flow in continuously by conveyor or other means. An ample supply of water is also introduced along with the sand and gravel, either as a part of the sand and gravel input or from a separate source of supply. The oscillation of the carriage causes the fines and material of intermediate size to be washed through screen 41 onto the bottom of pan 30. The coarse material works its way to the lower end of the screen and overflows flash board 42 for discharge from apron 45. The heaviest concentrates in pan 30 are retained by rifles 39 while the coarser and lighter materials are oscillated over the rifles and pass down through throat 52 to the lower pan.

The heaviest material arriving through throat 52 tends to remain in the lower rear end of the lower pan while the coarser and lighter material is displaced toward the front end of the lower pan. Meanwhile, the oscillations of the pendulous agitator 55 work the material back and forth in the lower pan, causing the material to stratify so that the uppermost and lighter material is moved forward and discharged over lip 47 along with the excess water at each oscillation of the carriage and pendulum. The heavier material on the bottom tends to move downward and backward toward wall 38. This produces a second panning operation in the lower pan which recovers concentrates not captured by the rifles 39 in the upper pan.

From time to time apron 45 and agitator 55 may be removed and the pans tilted up on pivots 33 to discharge material from the pans. Before doing this, of course, the excess sand and gravel may be pushed forward in the lower pan for careful removal of the concentrates at the lower rear end of the lower pan.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. An ore concentrating machine comprising a carriage mounted for oscillation in a longitudinal direction, an upper pan and a lower pan on said carriage, each of said pans having an overflow discharge end, said upper pan sloping downwardly towards its overflow discharge end and said lower pan sloping upwardly towards its overflow discharge end, a high end Wall at the lower end of the bottom of said lower pan and forming a deep end at said lower end, and a low end wall at the upper end of the bottom of said lower pan having an overflow discharge lip below the top of said high end wall, the lower end of said upper pan being arranged to discharge into said deep end of said lower pan at an elevation above the level of said discharge lip.

- 2. A machine as defined in claim 1 including rifles in the bottom of said upper pan, a sloping screen above said rifles, an upstanding flash board at the lower end of said screen, and a sloping apron for discharging coarse material which passes over said flash board.

3. A machine as defined in claim 2, said upper pan being disposed at one end of said lower pan opposite said discharge lip and said apron extending across said lower pan and above said discharge lip.

4. A machine as defined in claim 1 including a free swinging pendulous agitator in said lower pan.

5. A machine as defined in claim 1, said upper and lower pans being constructed as a rigid unit and pivotally connected with said carriage for tilting to an end up 7 position.

6. A machine as defined in claim 1 including a rod connected at one end with said carriage and extending in the direction of oscillation, a transverse stationary apertured abutment bar slidably receiving said rod, a coil spring on said rod compressed between said carriage and said bar, and a coil spring on said rod compressed between the free end of said rod and said bar.

7. A machine as defined in claim 6 including a motor having an output shaft with a crank, a pitm-an on said crank connected with said carriage for oscillating the carriage.

8. A machine as defined in claim 1 including wheels on said carriage, a base platform, level track rails on said platform for said wheels, and a motor on said platform for oscillating said carriage on its wheels.

9. A machine as defined in claim 1 including means for oscillating said carriage, a stationary spring abutment,

and an opposed spring combination connected with said carriage and abutment arranged to store energy during deceleration of the carriage in each excursion of its oscillation and impart said energy to the carriage during acceleration in the opposite direction after each reversal of its movement. v

10. A machine as defined in claim 1, the top of said high end wall being connected to the lower end of the bottom of said upper pan, said pans being mounted on said carriage in end to end relation.

11. A machine as defined in claim 1 including a vertical partition wall in said lower pan spaced from said high end wall to form a throat for the passage of ma. terial from said upper pan into said deep end of said lower pan, said partition having a lower end spaced above the bottom of the lower pan.

12. An ore concentrating machine comprising an upper pan and a lower pan arranged end to end and adapted to be oscillated in a longitudinal direction, a rifled bottom in said upper pan sloping toward said lower pan for discharge therein, a screen above said rifled bottom sloping toward said lower pan, a discharge apron extending from ing downwardly from said discharge lip and in a direction toward said upper pan, an end wall in the opposite end of said lower pan connected at its top with the lower end of the bottom of said upper pan at an elevation above the level of said discharge lip, and a free swinging pendulous agitator in said lower pan.

13. A machine as defined in claim 12 including a carriage supporting said pan, and a pivotal connection between said pans and one end of said carriage whereby said pans may be pivotally upended.

14. A machine as defined in claim 13 including an opposed spring combination connected with said carriage and arranged to store energy and impart stored energy to the carriage on each reversal of movement for maintaining an oscillating system with low energy input.

15. A machine as defined in claim 13 including ad- References Cited by the Examiner UNITED STATES PATENTS 151,044 5/ 1874 Mitchell 209437 X 859,354- 7/1907 Wall 209448 2,091,620 8/ 1937 Williams 209-437 X References Cited by the Applicant UNITED STATES PATENTS 420,933 2/1890 Gates. 1,098,183 5/1914 Signorette. 1,599,293 9/ 1926 Severance.

iustable height means supporting said p on the pp 15 FRANK W. LUTTER, Primary Examiner.

site end of the carriage. 

12. AN ORE CONCENTRATING MACHINE COMPRISING AN UPPER PAN AND A LOWER PAN ARRANGED END TO END AND ADAPTED TO BE OSCILLATED IN A LONGITUDINAL DIRECTION, A RIFFLED BOTTOM IN SAID UPPER PAN SLOPING TOWARD SAID LOWER PAN FOR DISCHARGE THEREIN, A SCREEN ABOVE SAID RIFFLED BOTTOM SLOPING TOWARD SAID LOWERPAN, A DISCHARGE APRON EXTENDING FROM THE LOWER END OF SAID SCREEN LENGHTWISE ACROSS SAID LOWER PAN, AN OVERFLOW DISCHARGE LIP ON ONE END OF SAID LOWER PAN BENEATH SAID APRON, A BOTTOM IN SAID LOWER PAN SLOPING DOWNWARDLY FROM SAID DISCHARGE LIP AND IN A DIRECTION TOWARD SAID UPPER PAN, AN END WALL IN THE OPPOSITE END OF SAID LOWER PAN CONNECTED AT ITS TOP WITH THE LOWER END OF THE BOTTOM OF SAID UPPER PAN AT AN ELEVATION ABOVE THE LEVEL OF SAID DISCHARGE LIP, AND A FREE SWINGING PENDULOUS AGITATOR IN SAID LOWER PAN. 